driven_table.H

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
 
 
# ifndef DRIVEN_TABLE_H
# define DRIVEN_TABLE_H
 
# include <aleph.H>
# include <tpl_dynArray.H>
# include <ah-errors.H>
# include <functional>
# include <memory>
# include <type_traits>
 
using Event_Fct [[deprecated("Use the templated Event_Table with std::function handlers instead")]]
  = void *(*)(void *);
 
template <typename Signature>
class Event_Table
{
public:
  using Event_Handler = std::function<Signature>;
 
protected:
  [[nodiscard]] virtual const Event_Handler* read_table(size_t i) const = 0;
 
  virtual void write_table(size_t i, Event_Handler&& event_fct) = 0;
 
  virtual void clear_slot(size_t i) = 0;
 
public:
  [[nodiscard]] virtual size_t size() const = 0;
 
  virtual ~Event_Table() = default;
 
private:
  void append_event_to_table(Event_Handler&& fct)
  {
    write_table(size(), std::move(fct));
  }
 
public:
  template <typename Callable>
  void register_event(const size_t index, Callable&& fct)
  {
    ah_range_error_if(index >= size()) << "Index out of range";
    ah_range_error_if(read_table(index) != nullptr) << "Index is already used";
 
    write_table(index, Event_Handler(std::forward<Callable>(fct)));
  }
 
  template <typename Callable>
  size_t register_event(Callable&& fct)
  {
    append_event_to_table(Event_Handler(std::forward<Callable>(fct)));
    return size() - 1;
  }
 
  void unregister_event(const size_t index)
  {
    ah_range_error_if(index >= size()) << "Index out of range";
    ah_range_error_if(read_table(index) == nullptr) << "Index is not used";
 
    clear_slot(index);
  }
 
  bool is_registered(const size_t index) const
  {
    return index < size() and read_table(index) != nullptr;
  }
 
  template <typename F>
  bool check(const size_t, F) const
  {
    return false;
  }
 
  template <typename... Args>
  auto execute_event(const size_t index, Args&&... args) const
  {
    ah_range_error_if(index >= size())
      << "index " << index << " out of range [0, " << size() << ')';
 
    const auto* event_fct = read_table(index);
 
    ah_range_error_if(event_fct == nullptr) << "Index is not used";
 
    return (*event_fct)(std::forward<Args>(args)...);
  }
};
 
 
template <>
class Event_Table<void*(void*)>
{
public:
  using Event_Handler = std::function<void*(void*)>;
 
protected:
  [[nodiscard]] virtual const Event_Handler* read_table(size_t i) const = 0;
 
  virtual void write_table(size_t i, Event_Handler&& event_fct) = 0;
 
  virtual void clear_slot(size_t i) = 0;
 
public:
  [[nodiscard]] virtual size_t size() const = 0;
 
  virtual ~Event_Table() = default;
 
private:
  void append_event_to_table(Event_Handler&& fct)
  {
    write_table(size(), std::move(fct));
  }
 
public:
  template <typename Callable>
  void register_event(const size_t index, Callable&& fct)
  {
    ah_range_error_if(index >= size()) << "Index out of range";
    ah_range_error_if(read_table(index) != nullptr) << "Index is already used";
 
    write_table(index, Event_Handler(std::forward<Callable>(fct)));
  }
 
  template <typename Callable>
  size_t register_event(Callable&& fct)
  {
    append_event_to_table(Event_Handler(std::forward<Callable>(fct)));
    return size() - 1;
  }
 
  void unregister_event(const size_t index)
  {
    ah_range_error_if(index >= size()) << "Index out of range";
    ah_range_error_if(read_table(index) == nullptr) << "Index is not used";
 
    clear_slot(index);
  }
 
  bool is_registered(const size_t index) const
  {
    return index < size() and read_table(index) != nullptr;
  }
 
  // Legacy check for void* function pointers - compares function addresses
  bool check(const size_t index, void* (*fct)(void*)) const
  {
    if (index >= size() || !is_registered(index))
      return false;
 
    const auto* handler = read_table(index);
    if (!handler)
      return false;
 
    // Get the target function pointer from std::function
    auto target = handler->template target<void* (*)(void*)>();
    return target && *target == fct;
  }
 
  // Special override for void*(void*) with default nullptr argument
  void* execute_event(const size_t index, void* input = nullptr) const
  {
    ah_range_error_if(index >= size())
      << "index " << index << " out of range [0, " << size() << ')';
 
    const auto* event_fct = read_table(index);
 
    ah_range_error_if(event_fct == nullptr) << "Index is not used";
 
    return (*event_fct)(input);
  }
};
 
 
template <typename Signature>
class Static_Event_Table : public Event_Table<Signature>
{
public:
  using Event_Handler = typename Event_Table<Signature>::Event_Handler;
 
private:
  std::unique_ptr<Event_Handler[]> table; 
  size_t size_table; 
 
  void verify_index(const size_t i) const
  {
    ah_range_error_if(i >= size_table) << "index out of range";
  }
 
  [[nodiscard]] const Event_Handler* read_table(const size_t i) const override
  {
    verify_index(i);
    return table[i] ? &table[i] : nullptr;
  }
 
  void write_table(const size_t i, Event_Handler&& event_fct) override
  {
    verify_index(i);
    table[i] = std::move(event_fct);
  }
 
  void clear_slot(size_t i) override
  {
    verify_index(i);
    table[i] = Event_Handler();
  }
 
public:
  [[nodiscard]] size_t size() const override { return size_table; }
 
  explicit Static_Event_Table(const size_t num_events = 0)
    : table(num_events > 0 ? new Event_Handler[num_events] : nullptr),
      size_table(num_events)
  {
  }
 
  Static_Event_Table(const Static_Event_Table&) = delete;
 
  Static_Event_Table& operator=(const Static_Event_Table&) = delete;
 
  Static_Event_Table(Static_Event_Table&& other) noexcept
    : table(std::move(other.table)), size_table(other.size_table)
  {
    other.size_table = 0;
  }
 
  Static_Event_Table& operator=(Static_Event_Table&& other) noexcept
  {
    if (this != &other)
      {
        table = std::move(other.table);
        size_table = other.size_table;
        other.size_table = 0;
      }
    return *this;
  }
 
  ~Static_Event_Table() override = default;
};
 
 
template <typename Signature>
class Dynamic_Event_Table : public Event_Table<Signature>
{
public:
  using Event_Handler = typename Event_Table<Signature>::Event_Handler;
 
private:
  DynArray<Event_Handler> table; 
 
  [[nodiscard]] const Event_Handler* read_table(const size_t i) const override
  {
    const Event_Handler& handler = table[i];
    return handler ? &handler : nullptr;
  }
 
  void write_table(const size_t i, Event_Handler&& event_fct) override
  {
    table[i] = std::move(event_fct);
  }
 
  void clear_slot(size_t i) override
  {
    table[i] = Event_Handler();
  }
 
public:
  [[nodiscard]] size_t size() const override { return table.size(); }
 
  explicit Dynamic_Event_Table(const size_t num_events = 0) : table(num_events)
  {
    // Initialize all slots with empty handlers to avoid DynArray access exceptions
    for (size_t i = 0; i < num_events; ++i)
      table[i] = Event_Handler();
  }
 
  Dynamic_Event_Table(const Dynamic_Event_Table&) = delete;
 
  Dynamic_Event_Table& operator=(const Dynamic_Event_Table&) = delete;
 
  Dynamic_Event_Table(Dynamic_Event_Table&&) noexcept = default;
 
  Dynamic_Event_Table& operator=(Dynamic_Event_Table&&) noexcept = default;
 
  ~Dynamic_Event_Table() override = default;
};
 
 
// =============================================================================
// Legacy Type Aliases for Backward Compatibility
// =============================================================================
 
using Legacy_Static_Event_Table
  [[deprecated("Use Static_Event_Table<Signature> with a typed signature instead")]]
  = Static_Event_Table<void*(void*)>;
 
using Legacy_Dynamic_Event_Table
  [[deprecated("Use Dynamic_Event_Table<Signature> with a typed signature instead")]]
  = Dynamic_Event_Table<void*(void*)>;
 
 
# endif